Can I crank with 12v but keep my 6v ign system

After ATF oil treatment to get valves free from sticking I?d like to crank fast to get rest of oil out and fresh gasoline in. How is this done? Would not like to damage ign system. Jumper cables available and a good 12v battery. That said I hope valves maybe would free also. For your info no other vehicles on the boatyard so towing is not an option.

Forgot to say the 6v system should work normally w its 6v battery.

Sir:
What model -9N, 2N, or 8N?
There is a RIGHT WAY and many WRONG WAYS to jump start your 6V/POS GRN system with a 12V/NEG GRN car/truck battery. NEVER, EVER jump from your 12-VOLT power source battery directly to your 6-VOLT battery as you could possibly explode it. Your wiring is equally as important too. A 6-VOLT battery on your tractor doesn't mean the rest of the wiring is correct. Is it? Verify yourself using the correct wiring diagrams, don't take someone else's word for it, and do not skip any steps or components. This all being said, there is no reason for you not try starting the tractor just the way it is. If it is all wired correctly as a 6V/POS GRN system, and the battery is good with a full sustainable charge, there should be no concerns whether it will start or not. Forget about the ATF -it won't hurt a thing. As for jump starting, you will be touching the ground jumper cable to the tractor frame and, this is the IMPORTANT step, the transmission HAS to be set in neutral gear because by jump starting you are bypassing the neutral starter switch and it will START IN GEAR. You will stand clear, block wheels, and ensure tractor is not in gear before making the ground connection to complete the circuit. From your 12V power source, keep engine off and ensure cables are not in the way of the fan blade, belts, or any other moving parts -you don't want any accidents. Connect the NEG (BLK, usually) battery cable connector to the starter "HOT" post, single post on 9N/2N starters, RH post on 8N solenoid. Start vehicle with 12V power source, stand clear of tractor, take POS (RED, usually) battery connector and touch a part of the metal tractor frame to complete the circuit. The tractor will try to turn over. DO NOT HOLD the GRN cable on for more than 15/20 seconds at a time. It's going to get HOT. Prolonged contact will result in damaging/burning up the cutout or VR. As first stated, best to try it as is first, leave jump starting as a last resort.

Tim Daley(MI)

See tip # 23.

Don't forget that you will need a power source for the ignition.
75 Tips

How is jumping the starter going to burn out the cut out?

I have a 1951 Ford car that could be hard to start sometimes and I put a small high amp 12 volt power chair battery in a separate mount under the hood and a 12 volt solenoid beside it. Wired it to a push button switch under the dash and when it get hard to start I just turn the ignition (6 volt) on and touch the button and it spins the heck out of it and it starts whether it wants to or not. I have to charge the 12 volt battery from time to time.

Zane

"....RH post on 8N solenoid." I believe you intended 'LH'. As, RH would connect the 12v battery in parallel with the 6v battery and you already cautioned against doing that.

Porsskar, what about just pulling the plugs and spinning it over for 30 or 40 seconds?

Thank you all for great support, the model is a 8nan but has never been used with kerosene only gasoline. The production year is 1949 w front mounted distributor. The wiring harness bought from original Ford and has never given a problem. All in all this tractor is in daily use since 1995 on my boatyard.

YES

It won't, my bad nor will it fry a VR.

TPD

Forgot to say the 6v system should work normally w its 6v battery.

(quoted from post at 07:03:43 08/03/18) Forgot to say the 6v system should work normally w its 6v battery.

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All you have to do is to jump to the starter side of the starter solenoid and the 6 volt system will not be changed at all. Just remember to make sure you have it out of gear. as soon as you connect the cables the starter will crank over. As suggested I would remove all the spark plugs and then turn it over with 12 volts, but with the plugs out 6 volts should turn it over pretty fast.

Reporting back: could not get the 6 v engine to fire after ATF traeatment for sticking valves. So I gave it a 12v treatment spinning for some 30 sek with the 6v system disconected. Must have given the valves some impact because the engine then fired with the 6v system normally connected one cylinder at the time, lots of white smoke for 15 minutes. Thank everybody great help!